Heating means



G. @R HM HEATING MEANS Aug. i967 3 Sheets-Sheet l Filed Sep. 14, 1964Aug- 1, 1967 G. GRAHAM 3,333,771

HEATING MEANS Filed Sept. 14, 1964 3 Sheets-Sheet 2 PA F164 L i@ i 4@ LL-A 1/5 FIGS G. GRAHAM HEATING MEANS Aug. 1, 1967 5 SheetS-Sheet FiledSept. 14, 1964 UnitedStates Patent O HEATING MEANS Geoffrey Graham,Bradford, England, assignor to Scandura Incorporated', Portland, MaineFiled Sept. 14, 1964, Ser. No. 405,319 Claims priority, applicationGreat Britain, Sept. 13, 1963,

4 Claims. (Cl. 237-1) This invention relates to heat generating unitsfor use in the vulcanising of beit joints in situations Where stringentfire precautions are considered necessary, for example as in coal mines.

It is common practice in coal mines to convey the coal from the coalface to the pit shaft by means of endless belt conveyors. Throughcontinual wear and abrasion, sections of the belting on the conveyorbecome damaged and have to be cut out and replaced by new lengths ofbelting which are incorporated in the conveyor by means of belt joints.These joints are frequently in the form of a vulcanised splice.

The two belt ends to be spliced are rst notched or otherwise serratedand coated with a bonding compound. The joint is effected by placing thetwo belt ends together between heated metal plates or platens andallowing the bonding compound to cure through the application of heat.It is essential when making a belt joint in a coal mine, that any heatdeveloped for the splicing operation must be obtained without the fearof sparks or naked ames being emitted.

Heretofore the platens have generally been heated by means of electriclilaments embedded therein. Current for the laments has been supplied byan electric transformer. However, in practice it has been found that theapparatus required for this type of heating is very heavy and cumbersomesince it normally involves numerous special ame-proof units for thetransformers, switchgear, thermostats and junction boxes between theseunits in order to render them ameproof.

It is therefore an object of the present invention to provide animproved heat generating unit for use in the vulcanising of belt jointsunder conditions of high explosion and lire risk.

It is a further object of the present invention to provide a heatgenerating unit which incorporates working chamber means which iscompletely ameproof.

It is a still further object of the present invention to provide aportable belt vulcanising unit which is hameproof and is far lighter andeasier to handle than ameproof belt vulcanising units which havehitherto been proposed.

According to the present invention there is provided a portable, beltvulcanising unit which includes a closed heating liquid circuit,circulating pump means in said circuit adapted to pump said heatingliquid through and round said circuit, energy conversion means in saidcircuit for converting mechanical energy into thermal energy adapted toeffect an increase in temperature of said heating liquid, and beltvulcanising platen means in said circuit adapted to be heated by saidheating liquid.

A heat generating unit incorporating the principle of conversion ofmechanical energy into thermal energy is well known; United StatesPatent 2,764,147 discloses a frictional heater for a hydraulic systemwhich works on the above principle. In one form, the means forconverting mechanical energy into thermal energy is a ro-` tatablemember capable of providing relative movement between itself and theheating liquid. The rotatable member, like the circulating pump can bedriven by a flameproof electric motor which is well known in the art. Itwill be realised however that other ameproof driving 3,333,771 PatentedAug. 1, 1967 ICC means may be used, for the operation of either or boththe pump and rotatable member, for example a compressed air operatedmotor.

The invention further provides for a pair of metal platens between whichthe belt joint is placed during the vulcanisation process. Each platenconsists of a metal plate which is embossed on its under surface with aseries of continuous grooves. A second metal plate is then welded ontothe under surface thus providing a series of internal passagewaysbetween the two plates. Inlet and outlet pipes are provided on the sidesof the platen to allow the heating liquid to circulate through theinternal passageways.

In the present form of the invention for the conversion of mechanicalenergy into thermal energy for use in the heat generating unit, heatingliquid is passed to a liquid charnber via the small inlet orifice by thecirculatory action of the vanes in the rotor chamber. From the liquidchamber the heated heating liquid is pumped into the platen or platensby means of a small centrifugal pump. The arrangement is such thatcontinual circulation of the heating liquid through the rotor chamberand then through the small inlet orifice into the liquid chamber andthence into the platen or platens causes a proportion of the mechanicalenergy of the heating liquid to be transformed to thermal energy and aconsequential rise in the temperature of the heating liquid.

One embodiment of the present invention will now be described by way ofexample only, and with reference to the accompanying diagrammaticdrawings in which:

FIG. l illustrates a heating liquid heating unit which includes therestricted orice, the liquid chamber, and rotor chamber and pipestherefrom through which heating liquid can pass to platens (to beconnected thereto);

FIG. 2 is an end elevation of the unit illustrated in FIG. l;

FIG. 3 is a plan view of the liquid chamber shown in FIG. 1 andillustrates an air jacket enclosing said chamber;

FIG. 4 illustrates a platen and shows the arrangement of the internalpassageways through the platen;

FIG. 5 illustrates the way in which the internal passageways of twoplatens are coupled;

FIG. 6 shows a cross-section on the lines A-A of FIG. 4 and illustratesa suitable form of construction of a platen;

FIG. 7 shows a rotor situated within the rotor chamber shown in FIG. 1for converting mechanical energy of the rotor into thermal energy toeffect an increase in temperature of the heating liquid; and

FIG. 8 is a side view of the vanes of the rotor illustrated in FIG. 7.

A ameproof electric motor 1 (see FIG. 1) is directly coupled to a rotorhoused in a rotor chamber 23 (to be described hereinafter with referenceto FIGS. 7 and 8); both the motor 1 and rotor chamber 23 are mounted ona common base plate 3. A liquid chamber 4 is mounted on the flanges ofinlet and outlet passages 5 and 6 respectively of the -rotor chamber 23.

Inside the liquid chamber 4 a pipe 7 extends from the outlet 6 of therotor chamber 23 to a variable pressure relief valve 8 which valve isadjusted by a handle 8a. The pipe 7 includes a small Xed orifice 9connected in parallel with the relief valve 8 through which orice liquidcar flow independently of the setting of the relief valve 8. Thedischarge of liquid from the relief valve 8 and the orifice 9 isconfined to the liquid chamber 4.

The liquid in the liquid chamber 4 is circulated througl pipe 4a to theplaten or platens (to be described herein after with reference to FIGS.4 to 6) and the pipe 4b b3 means of a small centrifugal pump 10 drivenby a belt 1I from the electric motor 1.

Also driven through the belt 11, by the electric motor 1, is acentrifugal air blower 12 which is operatively associated with an airjacket 13 that surrounds the liquid chamber 4 (see FIG. 3). The blower12 draws air through a filter 14 such that the airv passes around, andin contact with, the liquid chamber 4 where it becomes heated and theheated air used to dry the ends of a belt before splicing commences.

In combination with the air jacket 13 there is provided a plurality ofpassageways 13a situated within the liquid chamber itself. Air is causedto pass through the passageways 13a by use of the blower 12. .Inoperation, once the liquid chamber becomes hot, air can be passedthrough it and the heated air used for example, to dry the ends of abelt to be joined by vulcanising prior to such vulcanisation.

In order to obtain an efficient transfer of heat from the liquid chamberto the air in the air jacket 13 and in the air passageways 13a, thepassageways and the air jacket 13 are tightly packed with knitted copperwire 13b.

Referring now to FIGS. 4 to 6, which illustrate the platens forvulcanising a belt joint; the heating liquid passes through inlet pipe4a: to a duct 15 associated with a platen 16. The heating liquid flowsthrough the duct 15 and consequently transfers its yheat to the platen16. The heating liquid eventually passes via connecting pipe 17 to afurther platen 18 which is similarly heated. The heating liquid caneventually return through the pipe 4b to the heating unit to bereheated.

FIG. 6 illustrates a convenient way in which the duct 15 can be providedin the platen 16 by the liquid-tight connection of a liat metallic sheet19 and a suitably shaped metallic sheet 20, shaped for example bypressing, to provide a channel 15a. The two sheets 19 and 20 can beconveniently joined by Welding.

Referring now to FIGS. 7 and 8 which illustrate rotor means for heatingthe heating liquid; a rotor 21 having two sets of vanes 22 and 22a isrotatably mounted within the rotor chamber 23 on a rotor shaft 24 whichis coupled to the motor 1. 'Ihe rotor chamber 23 is sub-divided into twovane chambers 25 and 25a in which are respectively housed the sets ofvanes 22 and 22a. The vane chambers 25 and 25a are interconnected by aplurality of passages 26 radially disposed about the longitudinal axisof the shaft 24 to pass through a partition wall 27 which separates `:hetwo housings 25 and 25a. The rotor chamber 23 is grovided with the inletpassage through which liquid :an pass from the liquid chamber 4 into thevane housing Z5 and the outlet passage 6 through which liquid can passrom the vane housing 25a to the liquid chamber 4.

The vanes 22 and 22a of the rotor 21 are suitably haped and, if desired,perforated as at 31 to provide an `flicient rate of heating to liquidflowing through the lousings 25 and 25a when the rotor 21 is rotatedtherein. t will be realised that the moving vanes provide, in additon tothe property of raising the temperature of the quid, an eliicient pumpfor circulating the heating liquid round the liquid circuit and ifnecessary this pumping ction can replace the small centrifugal pump 10.

Inserted in the inlet passage 5 of the rotor chamber 23 a liquid flowcontrol valve 5a adjustment of which valve rovides an eiicient method ofcontrolling the iiow of :ating liquid from the liquid chamber 4 to therotor lamber 23.

In operation of the heat generating unit as above deribed andillustrated with reference to FIGS. 1 to 3,

and 8 the supply and return pipes 4a and 4b are coupled the pai-r ofplatens illustrated in FIG. 5; the flameproof ectric motor 1 is turnedon and the centrifugal rotor 21 tates in its housing. Heating liquid isdrawn from the luid chamber 4 by the pumping effect of the rotor 21,

sses through the valve 5a, inlet 5 and rotor housing 23 3m which it iseventually discharged via the outlet 6 d through the small xed orifice 9(and if desired the riable relief valve 8) and back into the liquidchamber The continual circulation of the liquid through the 4 smallfixed orice 9 and the rotation of the rotor 21 in its housing 23 causeswork to be done on the liquid and a consequent increase in itstemperature. The temperature of the liquid continues to rise untileventually it boils and in this respect the unit can be self regulatingwith regard to temperature. The heated heating liquid in the liquidchamber 4 is drawn through the liquid supply pipe 4a by the smallcentrifugal supply pump lil-and passes through the platens 16 and 18 aspreviously described to cause them to be heated. The liquid eventuallyreturns through pipe 4b to the liquid chamber 4 where it passes throughthe process of reheating. The heated platens can then be utilised forvulcanising belt joints by a method well known in the art.

By suitable adjustment of the flow control valve 5a and of the variablerelief valve 8, sensitive control on the temperature of the heatingliquid can be obtained.

When the heating liquid is such that it does not emit a harmful orobjectionable vapour then the liquid chamber 4 may be vented for thepurpose of releasing this vapour; the inclusion of this vent isespecially advantageous in the case when excess power supplied by theelectric motor is dissipated as a vapour in the liquid chamber.

During the initial heating up period of the liquid and in order toobtain the maximum rate of temperature rise, the relief valve 8 isscrewed fully closed thus causing all the liquid delivered from the pumpto pass through the small fixed orifice 9. As would be expected theworking characteristics of the rotor used are such that the maximumpressure developed under operational conditions is well within thebursting strength of the rotor housing, similarly the electric motor 1is such that it does not become overloaded on the maximum workingstresses..

It will be seen that since liquid is utilised as the heating medium theboiling point of the liquid can be chosen to suit a particular beltingmaterial in which a joint is to be vulcanised. For example, in themaln'ng of vulcanised joints for belting according to British patentspecification No. 901,197 a temperature of C. is required and water isthus suitable to use. Conversely ethyleneglycol may be added to theWater in which case the boiling point is raised to C. or more dependingupon the ratio of ethyleneglycol to water, and it is usually thismixture which is preferred for temperatures in the region of 100 to 120C. If higher temperatures still are required, liquids of higher boilingpoint may be used, and if their vapours are harmful or objectionable, asis usually the case, the vent from the liquid chamber would be connectedto a suitable reflux condenser.

It is to be noted that the maximum temperature obtainable in the heatingunit is controlled by the boiling point of the liquid used, butalternatively normal thermostatic control may be utilised. Preferably anon-electric type would be used, for example an expanding capsuleoperating a relief valve. This arrangement would permit the use ofnon-inammable and innocuous liquids,` for example, glycerine, attemperatures below the level of the boiling points.

I claim:

1. A portable, belt vulcanising unit which includes a closed heatingliquid circuit, circulating pump means in said circuit adapted to pumpsaid heating liquid through and round said circuit, energy conversionmeans in said circuit for converting mechanical energy into thermalenergy adapted to effect an increase in temperature of said heatingliquid, and belt vulcanising platen means in said circuit adapted to beheated by said heating liquid.

2. A belt vulcanizing unit which includes a closed heating liquidcircuit, a heat producing restrictor in said circuit, a rotor chamber insaid circuit, a heat producing vaned rotor housed in said rotor chamber,driving means for imparting rotational movement to said rotor, and beltvulcanizing platen means in said circuit.

3. A belt vulvanizing unit according to claim 2 wherein 5i said heatproducing restrictor defines an inlet orifice to a liquid chamber insaid circuit.

4. A belt vulcanizing unit according to claim 3 wherein said circuitincludes an adjustable, by-pass, relief valve connected in said circuitin parallel with said restrictor to communicate with said liquid chamberwhereby adjustment of said relief valve can cause heating liquid owinginto said liquid chamber to by-pass said restrictor.

References Cited UNITED STATES PATENTS Thomson 122-26 Ewers 156-583 XAllen 126-247 Walker 122-26 Wagner 165-162 Roe 110-56 Kenney 122-26 XBrunner 126-247 Rizzo 165-121 X Kimm 126-247 X ROBERT A. OLEARY, PrimaryExaminer.

A. W. DAVIS, Assistant Examiner.

1. A PORTABLE, BELT VULCANISING UNIT WHICH INCLUDES A CLOSED HEATINGLIQUID CIRCUIT, CIRCULATING PUMP MEANS IN SAID CIRCUIT ADAPTED TO PUMPSAID HEATING LIQUID THROUGH AND ROUND SAID CIRCUIT, ENERGY CONVERSIONMEANS IN SAID CIRCUIT FOR CONVERTING MECHANICAL ENERGY INTO THERMALENERGY ADAPTED TO EFFECT AN INCREASE IN TEMPERATURE OF SAID HEATINGLIQUID, AND BELT VULCANISING PLATEN MEANS IN SAID CIRCUIT ADAPTED TO BEHEATED BY SAID HEATING LIQUID.